Jason -
Looks very good. As someone who looks at a lot of software resumes, my opinion is that this is solid.
One thing read a little weird: "designed gameplay in various interactives". Have not heard "interactives" used as a noun before. Might suggest changing it to "Designed gameplay for interactive trade show booth attractions" or "for interactive, large-screen demos" or something like that.
Regarding cover letters -- pretty much any and all hiring happens by email or a web site these days. I have not seen a cover letter in years. Probably good to have some text, but lilkely it will be highly tailored to the job you're applying for.
Nice work.